A woman has drowned at Tahunanui Beach in Nelson.
Police said a man and a woman got into trouble while swimming at low tide in their clothing at about 1.30am and struggled to get to the shore.
The man managed to pull the 29-year-old woman out of the water, but she died at the scene.
Nelson Surf Lifesaving Club president Marcus Gardner said there were hidden dangers at Tahunanui Beach.
"The blind channel at the western end of the beach has a strong tidal outflow and is quite deep."
Swimming clothed was a high-risk activity, and anyone in the ocean at night be aware of which part of the beach they were on, he said.
The man was taken to Nelson Hospital and was in a moderate condition.